Conventional lithography technology for manufacturing a semiconductor device includes double patterning technology by ArF liquid immersion exposure, EUV lithography, nano-imprint, etc. With the miniaturization of the pattern, the conventional lithographic technology suffers various problems, such as an increase in cost, and a decrease in throughput.
Under such circumstances, application of the self-assembly (DSA: Directed Self-assembly) to a lithography technology has been explored. Since self-assembly is caused by a spontaneous behavior called energy stability, the self-assembly can form a pattern with high dimensional accuracy. In particular, the technology of using microphase separation of the polymer block copolymer can form the periodic structure of various shapes in several to several hundred nanometers (nm) in a simple coating and annealing process. By changing the shape into a sphere, cylinder, and lamella, etc. according to the composition ratio of a high molecular block copolymer, and changing size according to a molecular weight, the dot pattern of various sizes, a hole or a pillar pattern, a line pattern, etc. can be formed.
In order to form a desired pattern extensively using DSA, it is necessary to prepare an epitaxy that controls the generating position of the polymer phase formed by self-assembly. Epitaxy may include a structure consisting of a plurality of projected surfaces and a plurality of depressed surfaces, and the following epitaxies have been known: graphoepitaxy that forms a microphase separation pattern in a depressed portion of the structure, and chemical epitaxy that is formed in a lower layer of DSA material, and controls the formation position of a microphase separation pattern based on a difference in the surface energy.
When chemical epitaxy is used, a microphase separation pattern can be formed all over a substrate (e.g., wafer). However, when graphoepitaxy is used, a microphase separation pattern cannot be formed on the projected portion of the graphoepitaxy, and the substrate is not able to be used effectively as a portion of the substrate cannot be patterned.